US5732169A - Filter for guided light, and an optical link including the filter - Google Patents

Filter for guided light, and an optical link including the filter Download PDF

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Publication number
US5732169A
US5732169A US08/577,765 US57776595A US5732169A US 5732169 A US5732169 A US 5732169A US 57776595 A US57776595 A US 57776595A US 5732169 A US5732169 A US 5732169A
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United States
Prior art keywords
filter
gratings
line
differences
gain
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Expired - Fee Related
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US08/577,765
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English (en)
Inventor
Isabelle Riant
Pierre Sansonetti
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Oclaro North America Inc
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Alcatel Submarcom SA
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Application filed by Alcatel Submarcom SA filed Critical Alcatel Submarcom SA
Assigned to ALCATEL SUBMARCOM reassignment ALCATEL SUBMARCOM ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RIANT, ISABELLE, SANSONETTI, PIERRE
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Assigned to AVANEX CORPORATION reassignment AVANEX CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ALCATEL
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
    • G02B6/29356—Interference cavity within a single light guide, e.g. between two fibre gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
    • G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
    • H01S3/10023—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by functional association of additional optical elements, e.g. filters, gratings, reflectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S2301/00—Functional characteristics
    • H01S2301/04—Gain spectral shaping, flattening

Definitions

  • the present invention relates to optical filtering. More particularly, it is applicable to optical fiber telecommunications systems with spectrum multiplexing, and still more particularly to optical links using solitons.
  • Optical fiber links typically include amplifiers for compensating line losses.
  • Fabry-Perot filters with a transmission coefficient having a maximum in each of the multiplexed spectrum channels. More particularly, in soliton links with spectrum multiplexing, such filters also serve to avoid drift in soliton wavelength.
  • a particular object of the present invention is to eliminate, or at least to limit, such differences in level.
  • the invention provides a filter for guided light, the filter including two Bragg gratings following one another in a common light guide and leaving between them a gap so that together they constitute a Fabry-Perot filter whose transmission coefficient presents a succession of local maxima as a function of wavelength, wherein the two gratings differ mutually, thereby introducing differences between the values of said local maxima in transmission coefficient.
  • FIG. 1 shows a filter analogous to a known filter.
  • FIG. 2 shows a filter of the preferred embodiment.
  • FIGS. 3 and 4 are respective graphs for the above two filters, showing variation in transmission coefficient as a function of wavelength plotted along the abscissa.
  • FIG. 5 shows a link using the filter of the invention.
  • a filter of the present invention comprises two Bragg gratings R1 and R2 that follow one another along a common light waveguide G so that each of them reflects a portion of the guided light to be filtered. Between them, these two gratings is a gap DS so that together they constitute a Fabry-Perot filter whose transmission coefficient presents a succession of local maxima M1, . . . , M10 as a function of wavelength. These two gratings differ mutually in such a manner as to impart differences between the values of the local maxima in transmission coefficient. These differences may be used, in particular, to compensate for the unwanted differences in level that appear between waves whose wavelengths coincide with respective local maxima. This difference between the two Bragg gratings is advantageously a difference in their respective lengths L1 and L2.
  • each of the two gratings is a fixed-pitch grating and the tuning wavelengths and the refractive index contrasts of the two gratings are identical. It would nevertheless be possible to use a difference in contrast, but that would be more complex to implement.
  • the light guide G is typically an optical fiber.
  • the filter of FIG. 1 is analogous to that described in the article "Fiber Fabry-Perot interferometer using side exposed fiber Bragg gratings", by W. W. Morey, T. J. Bailey, W. H. Glenn, and G. Meltz, published in OFC'92, WA2, on page 96. It comprises a waveguide G' having two identical gratings R'1 and R'2 of length 0.25 mm that are spaced apart by a distance of 2.06 mm and that are tuned to a wavelength of about 1,558 nm.
  • the gratings R1 and R2 of the filter F in FIG. 2 have respective lengths of 0.25 mm and of 0.35 mm and they are separated by a distance of 2.01 mm, with the tuned wavelength being the same as above.
  • the graphs of FIGS. 3 and 4 are computed for the case where phase matching is achieved between the two Bragg gratings, as can be done, in particular, by making both gratings in a single inscription operation. Such an operation can be performed using known methods.
  • the present invention provides an optical fiber link, in particular a soliton link, that uses the above-described filter.
  • This optical fiber link includes the following elements:
  • An emitter E for emitting information-carrying optical signals occupying channels that are regularly spaced apart in a spectrum band constituting a transmission band. Typically, in each channel, these signals present the form of solitons.
  • Line fibers G1, . . . , Gn that follow one another in series to make up a line that conveys the signals.
  • At least one amplifier A inserted in series in the line.
  • the amplifier comprises a succession of erbium-doped optical fiber amplifiers. They are used to compensate for line losses.
  • Each amplifier presents gain in each of the channels.
  • a graph of said gain as a function of the center wavelength of each channel typically presents a curve constituting a gain curve.
  • the filter is typically constituted by a succession of filters each associated with a respective amplifier.
  • Each filter comprises two Bragg gratings R1, R2 following each other along a light guide G that is typically constituted by a fiber connected in series in the link.
  • the two gratings follow one another a gap DS therebetween so that together they constitute a Fabry-Perot type filter whose transmission coefficient as a function of wavelength presents a regular succession of local maxima M1, . . . , M10 as can be seen in FIG. 4.
  • These maxima coincide with the center wavelengths of the channels.
  • These center wavelengths are preferably distributed symmetrically over the local maxima about the corresponding central minimum C in the transmission coefficient.
  • a receiver H serves to receive the optical signals output by the line and to restore the information carried by the signals.
  • the link made in this way presents composite gain that increases with the gain of each amplifier for the channel.
  • the composite gain also increases with a local maximum in the transmission coefficient of each filter, the maximum being the maximum that coincides with the center wavelength of the channel.
  • the composite gain for each channel is proportional to the product of the amplifier gain multiplied by the local maximum of the transmission coefficient of the filter. Nevertheless, when line losses are taken into account, the composite gain over one amplification step is typically zero, when expressed in decibels.
  • the two gratings R1 and R2 of the filter F i.e. of at least one filter and preferably of all of the filters in the above-mentioned succession, present a mutual difference that imparts useful differences between the values of the local maxima in transmission coefficient of the filter, which useful differences are suitable for compensating, at least in part, the unwanted differences between the composite gains of the various channels in the link and due to other causes.
  • the desired object is to achieve equal composite gains for all of the channels.
  • each filter is used to compensate the gain curve of an associated amplifier in the line which itself includes numerous amplifiers. Compensation is thus distributed along the length of the line. This is particularly desirable in a soliton link since the energy of a soliton must be subject to variations that are limited, only.
  • the difference between the two gratings of the filter is preferably merely a difference in the lengths of the gratings.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optical Communication System (AREA)
  • Lasers (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Light Guides In General And Applications Therefor (AREA)
  • Optical Filters (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)
US08/577,765 1994-12-28 1995-12-22 Filter for guided light, and an optical link including the filter Expired - Fee Related US5732169A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9415792 1994-12-28
FR9415792A FR2728975A1 (fr) 1994-12-28 1994-12-28 Filtre pour lumiere guidee et liaison optique incluant ce filtre

Publications (1)

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US5732169A true US5732169A (en) 1998-03-24

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Country Status (5)

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US (1) US5732169A (enrdf_load_stackoverflow)
EP (1) EP0721121A1 (enrdf_load_stackoverflow)
JP (1) JPH08234051A (enrdf_load_stackoverflow)
CA (1) CA2166178A1 (enrdf_load_stackoverflow)
FR (1) FR2728975A1 (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5986790A (en) * 1996-03-05 1999-11-16 Fuji Xerox, Co., Ltd. Light source for optical communication, optical transceiver and optical communication network
US6044189A (en) * 1996-12-03 2000-03-28 Micron Optics, Inc. Temperature compensated fiber Bragg gratings
US6115122A (en) * 1996-10-18 2000-09-05 Micron Optics, Inc. Fabry-perot fiber bragg grating multi-wavelength reference
EP1033794A4 (en) * 1998-07-07 2002-10-02 Furukawa Electric Co Ltd OPTICAL GAIN EQUALIZER AND OPTICAL AMPLIFIER AND WAVELENGTH MULTIPLEX TRANSMITTER HAVING TWO SAID OPTICAL GAIN EQUALIZER
US6636666B2 (en) 2001-05-14 2003-10-21 University Of Iowa Research Foundation Optical power equalizer
KR100426624B1 (ko) * 2000-11-01 2004-04-08 병 호 이 전광 게이팅/변조 소자
US20040151438A1 (en) * 2002-12-20 2004-08-05 Ferguson Stephen K. Temperature compensated ferrule holder for a fiber Fabry-Perot filter
US20040247244A1 (en) * 2002-10-15 2004-12-09 Yufei Bao Waferless fiber fabry-perot filters
US20050254062A1 (en) * 2003-11-06 2005-11-17 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US20060154320A1 (en) * 2005-01-07 2006-07-13 Fortebio, Inc. Enzyme activity measurement using bio-layer interferometry
US20080144039A1 (en) * 2003-11-06 2008-06-19 Fortebio, Inc. Fiber-Optic Assay Apparatus Based on Phase-Shift Interferometry
US20100054288A1 (en) * 2005-10-13 2010-03-04 Sensilaser Technologies Inc. Method and Device for Reducing Laser Phase Noise
US20100093106A1 (en) * 2006-09-14 2010-04-15 Fortebio, Inc. Amine-Reactive Biosensor
CN101320110B (zh) * 2008-06-07 2011-04-06 厦门大学 可调谐相移光纤布喇格光栅
US20120237162A1 (en) * 2009-09-18 2012-09-20 Fraunhofer-Gesellschaft Zur Foerderung Der Angewan Transverse mode filter for waveguides
US8647588B2 (en) 2005-06-13 2014-02-11 Pall Corporation Tip tray assembly for optical sensors

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19629530C1 (de) * 1996-07-22 1997-10-30 Univ Dresden Tech Faseroptischer Kodierer/Dekodierer
GB9809583D0 (en) 1998-05-06 1998-07-01 Marconi Gec Ltd Optical devices
CN114812630B (zh) * 2022-07-01 2022-09-20 中北大学 基于波导光栅的双参数原位传感器、传感系统及制备方法

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EP0435217A2 (en) * 1989-12-26 1991-07-03 United Technologies Corporation Embedded Bragg grating pumped lasers
EP0463771A2 (en) * 1990-06-22 1992-01-02 AT&T Corp. Multi-stage optical fiber amplifier
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US5400422A (en) * 1993-01-21 1995-03-21 The United States Of America As Represented By The Secretary Of The Navy Technique to prepare high-reflectance optical fiber bragg gratings with single exposure in-line or fiber draw tower
US5561675A (en) * 1994-05-20 1996-10-01 France Telecom Linearly polarized fiber-optic laser
US5615008A (en) * 1994-12-21 1997-03-25 Beckman Instruments, Inc. Optical waveguide integrated spectrometer

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US5317576A (en) * 1989-12-26 1994-05-31 United Technologies Corporation Continously tunable single-mode rare-earth doped pumped laser arrangement
EP0463771A2 (en) * 1990-06-22 1992-01-02 AT&T Corp. Multi-stage optical fiber amplifier
WO1993024977A1 (en) * 1992-06-01 1993-12-09 British Telecommunications Public Limited Company Filter with preselected attenuation/wavelength characteristic
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E. Delevaque et al, Gain control in erbium doped fibre amplifiers by lasing at 1480 nm with photo induced bragg gratings wirtten on fibre ends , Electronics Letters, vol. 29, No. 12, 10 Jun. 1993, Enage GB, pp. 1112 1114. *
R. Kashyap et al, "Wavelength Flattened Saturated Erbium Amplifier Using Multiple Side-Tap Bragg Gratings", Electronic Letters, vol. 29, No. 11, 27 May 1993, Enage GB, pp. 1025-1026.
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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5986790A (en) * 1996-03-05 1999-11-16 Fuji Xerox, Co., Ltd. Light source for optical communication, optical transceiver and optical communication network
US6115122A (en) * 1996-10-18 2000-09-05 Micron Optics, Inc. Fabry-perot fiber bragg grating multi-wavelength reference
US6327036B1 (en) 1996-10-18 2001-12-04 Micron Optics, Inc. Fabry Perot/fiber Bragg grating multi-wavelength reference
US6044189A (en) * 1996-12-03 2000-03-28 Micron Optics, Inc. Temperature compensated fiber Bragg gratings
EP1033794A4 (en) * 1998-07-07 2002-10-02 Furukawa Electric Co Ltd OPTICAL GAIN EQUALIZER AND OPTICAL AMPLIFIER AND WAVELENGTH MULTIPLEX TRANSMITTER HAVING TWO SAID OPTICAL GAIN EQUALIZER
KR100426624B1 (ko) * 2000-11-01 2004-04-08 병 호 이 전광 게이팅/변조 소자
US6636666B2 (en) 2001-05-14 2003-10-21 University Of Iowa Research Foundation Optical power equalizer
US20040247244A1 (en) * 2002-10-15 2004-12-09 Yufei Bao Waferless fiber fabry-perot filters
US6904206B2 (en) 2002-10-15 2005-06-07 Micron Optics, Inc. Waferless fiber Fabry-Perot filters
US20040151438A1 (en) * 2002-12-20 2004-08-05 Ferguson Stephen K. Temperature compensated ferrule holder for a fiber Fabry-Perot filter
US7063466B2 (en) 2002-12-20 2006-06-20 Micron Optics, Inc. Selectable and tunable ferrule holder for a fiber Fabry-Perot filter
US20050254062A1 (en) * 2003-11-06 2005-11-17 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US7656536B2 (en) 2003-11-06 2010-02-02 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US20080144039A1 (en) * 2003-11-06 2008-06-19 Fortebio, Inc. Fiber-Optic Assay Apparatus Based on Phase-Shift Interferometry
US7394547B2 (en) 2003-11-06 2008-07-01 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US20080186505A1 (en) * 2003-11-06 2008-08-07 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US7728982B2 (en) 2003-11-06 2010-06-01 Fortebio, Inc. Fiber-optic assay apparatus based on phase-shift interferometry
US20060154320A1 (en) * 2005-01-07 2006-07-13 Fortebio, Inc. Enzyme activity measurement using bio-layer interferometry
US7445887B2 (en) 2005-01-07 2008-11-04 Fortebio, Inc. Enzyme activity measurements using bio-layer interferometry
US8647588B2 (en) 2005-06-13 2014-02-11 Pall Corporation Tip tray assembly for optical sensors
US20100054288A1 (en) * 2005-10-13 2010-03-04 Sensilaser Technologies Inc. Method and Device for Reducing Laser Phase Noise
EP1935069A4 (en) * 2005-10-13 2011-03-09 Sensilaser Technologies Inc METHOD AND DEVICE FOR REDUCING LASER PHASE RUSH
US7970032B2 (en) 2005-10-13 2011-06-28 Sensilaser Technologies Inc. Method and device for reducing laser phase noise
US20100093106A1 (en) * 2006-09-14 2010-04-15 Fortebio, Inc. Amine-Reactive Biosensor
CN101320110B (zh) * 2008-06-07 2011-04-06 厦门大学 可调谐相移光纤布喇格光栅
US20120237162A1 (en) * 2009-09-18 2012-09-20 Fraunhofer-Gesellschaft Zur Foerderung Der Angewan Transverse mode filter for waveguides
US8891917B2 (en) * 2009-09-18 2014-11-18 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Transverse mode filter for waveguides

Also Published As

Publication number Publication date
AU687281B2 (en) 1998-02-19
JPH08234051A (ja) 1996-09-13
EP0721121A1 (fr) 1996-07-10
FR2728975B1 (enrdf_load_stackoverflow) 1997-02-07
FR2728975A1 (fr) 1996-07-05
AU4074495A (en) 1996-07-04
CA2166178A1 (fr) 1996-06-29

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